Calculation of the field dependence of the rates of emission of carriers from deep centers based on an experimental form-function for the optical transition

An algorithm is proposed for calculating the field dependence of the emission rates based on a form-function for the optical transition. A comparison is made with experimental data for the V_GaS_As complex in gallium arsenide. This scheme for calculating the field dependence is found to be preferable to methods based on a single-coordinate model. Zh. éksp. Teor. Fiz. 116, 1027–1034 (September 1999)     

Study of the time dependence of ionic crystal cathodoluminescence under conditions of electron-stimulated self-activation

A physical model with a variable number of emission centers is considered for calculating the time dependence of activated cathodoluminescence intensity. A system of two kinetic equations is solved to calculate I(t). The main model parameters are determined. The theoretical results are compared with the experimental data and their good correspondence is demonstrated.     

Semimicroscopic description of basic modes of relaxation of the Gamow-Teller resonance

Semimicroscopic approach based on the continuum version of the random-phase approximation and on a phenomenological method for taking into account the fragmentation effect is used to describe quantitatively basic relaxation parameters of the Gamow-Teller resonance in magic and nearmagic nuclei. For the ²⁰⁸Bi nucleus, the results obtained by calculating the resonance parameters in question are compared with respective experimental data.     

Silicon fragmentation under the effect of high-energy cosmic-ray protons

The results obtained by calculating the cross sections for the elastic and inelastic scattering of 50- to 1000-MeV protons interacting with ²⁸Si, which is the main integrated-circuit element of onboard spacecraft electronics, are presented along with the calculated mass, charge, and energy distributions of heavy products of respective nuclear reactions. To compare the results of the calculations with experimental data, similar calculations were performed for the p + ²⁷Al reaction. This comparison shows that the elasticand inelastic-scattering cross sections calculated by using the EMPIRE-II-19 code are in satisfactory agreement with available experimental data. Considerably wider scatter of available data is observed in the isotope and isobar yields. A high sensitivity of the kinetic spectrum of the final nuclei to the incident-proton energy is demonstrated.     

Al、Cu、Ta高压熔化曲线的理论计算

由位错熔化理论和不同的静高压实验数据优化的体模量(B0)、剪切模量(G0)及它们对压力的一阶偏导数(B′0、G′0)值计算了Al、Cu、Ta的高压熔化曲线.理论计算的Al、Cu高压熔化曲线与静、动高压实验值较为吻合,Ta的理论高压熔化曲线与动高压实验结果一致,但与静高压实验结果相差较大.     

Universally Treating the Quark Pair with a Vacuum Quantum Number in the Related Charm Decays

A method for universally treating the quark pair with a vacuum quantum number is proposed and it is applied to calculating some charm meson decays zs examples. The smallness for W-exchange and annihilation mechanisms has new explanation and the result obtained by means of the proposed method on the D_s⁺→f0π⁺ de cay fits the experimental data well.     

Calculation of higher-order approximations of the coefficients of the Herman-Wallis factor. Test for hydrogen halides

The higher-order approximations of the perturbation theory for the Herman-Wallis factor, which describes the effect of the vibrational-rotational interaction on the matrix elements of dipole moments of diatomic molecules, are calculated within the formalism of quantum number polynomials. An algorithm for taking into account higher orders of the perturbation theory for calculating random coefficients is found; the algorithm has a better convergence than previous theoretical methods. As applied to hydrogen halides, the results obtained agree well with current experimental data.     

强流电子束碰撞电离背景气体研究

利用数值计算与粒子模拟两种方法,结合实际的实验数据,对高功率微波二极管中相对论电子束与背景气体相互作用碰撞产生的等离子体密度进行了研究.研究结果表明：碰撞产生的等离子体密度数值计算结果与粒子模拟结果基本一致,背景气压在0.01 Pa—0.05 Pa时,碰撞产生的等离子体密度在4—12×10⁹cm^-3,即便在考虑电子离子复合的情况下,数值计算结果与粒子模拟结果依然符合得很好.另外,粒子模拟结果表明：随着气压的增加,等离子体密度呈现先增大再减小然后又逐渐增大的过程, 关键词： 相对论电子束 等离子体 数值计算 粒子模拟     

Improvement of the Mathematical Model for Determining the Dose for the TV-Type Detector in Proton Dosimetry

The results on the improvement of the mathematical model for calculating the TV-type detector are presented. The parameters of the analytical formula valid for proton energies from 60 to 200 MeV, based on the combination of parabolic cylinder functions and consistent with numerical methods and new experimental data, are determined.     

Calculation of the speed of sound in reciprocal systems from the known ion concentrations

A method of calculating the deviations of the speed of sound in a mixed solution containing two types of cations and two types of anions from the speed of sound in pure water by using the known ion concentrations in the solution and the concentration dependences of the speed of sound in binary solutions of the salts entering the mixed solution is proposed. The method is based on the ionic strength rule and the equiprobable ion distribution hypothesis. The calculated values of the deviations of the speed of sound in a mixed solution from the speed of sound in pure water (for solution temperatures of 15 and 25°C) are in fairly good agreement with experimental data. The proposed method is applied for calculating the speed of sound in seawater.     

On the size dependences of the crystal-liquid phase transition parameters

A comparatively simple method is proposed for calculating the size dependences of the latent heat, volume jumps, and the interfacial surface energy for the crystal-liquid phase transition proceeding from the results of experiments (real or computer) on determining size dependences of the melting point and the crystallization temperature. The method is tested on the basis of computer simulation data for copper, gold, aluminum, and nickel nanoparticles and experimental data for tin.     

Calculating lateral distribution functions of the Cherenkov light from extensive atmospheric showers in terms of a multilevel scheme

A new technique for calculating the lateral distribution function of the Cherenkov light in very-high-energy extensive atmospheric showers is proposed. It is shown that the calculation results are in good agreement with the experimental data.     

Simulation of the intensity of X-ray tube radiation in soft X-ray and extreme UV regions

A program for calculating the fluorescence of target materials in X-ray tubes under electron irradiation with energies up to 15 keV is described. This program is based on simulation of the interaction of accelerated electrons with the target material by the Monte Carlo method. The calculated radiation intensity for the SiL _α characteristic line and the bremsstrahlung of a tungsten target are compared with the experimental data.     

Establishment of a dynamic model for the p-Ge far IR laser

Using new experimental data from modeling the p-Ge laser pulse plus literature data, basic laser parameters are obtained so that one can solve the laser equations of Pantell and Puthoff to obtain formulas for calculating all laser quantities of interest. Values, calculated using the formulas, such as gain, saturation intensity, pump population differences, power generated, output coupling, efficiency, etc. are in excellent agreement with available experimental data. This work contributes to problems in determining laser line transitions, the laser cycle, and the optimization of the laser performance.     

Experimental feasibility of phaseless inverse scattering methods for specular reflectivity

The possibilities for calculating the X-ray or neutron scattering potential across a thin film from experimental specular reflectivity amplitude information alone and using full dynamical theory, i.e., phaseless inverse scattering, are investigated and compared with traditional fitting methods. The feasibility of the method is demonstrated by one trivial and two non-trivial experimental examples. The usefulness, but also the limitations are outlined by the experiments and by numerical examples. The data reduction is treated in some detail and, in particular, a new method is proposed for deconvolving the experimental data from the instrumental smearing function. Received 19 May 1999     

Nonperturbative shell correction to the Bethe-Bloch formula for the energy losses of fast charged particles

A simple method including nonperturbative shell corrections has been developed for calculating energy losses on complex atoms. The energy losses of fast highly charged ions on neon, argon, krypton, and xenon atoms have been calculated and compared with experimental data. It has been shown that the inclusion of the non-perturbative shell corrections noticeably improves agreement with experimental data as compared to calculations by the Bethe-Bloch formula with the standard corrections. This undoubtedly helps to reduce the number of fitting parameters in various modifications of the Bethe-Bloch formula, which are usually determined semiempirically.